I was debugging an app at a customer site and we found a weird bug where some images would load up in the background at launch but no new ones would. They would always load fine in the foreground however. After much debugging we determined that loading a bad image, say with a url of "" in the background would kill a worker thread. If you do this enough times (4 appears to be the magic number) then there are no worker threads left to load more images and all background image loading fails. The code below demonstrates this bug. The initial loop creates some bad images. Then you can click on the red rectangle to try loading more images. If you create 3 or less bad images then you are okay. If you create 4 or more bad images then the later images can't load.


/*
 * Main.fx
 *
 * Created on May 21, 2009, 2:07:12 PM
 */

package test;

import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.*;
import javafx.scene.shape.*;
import javafx.scene.paint.*;
import javafx.scene.image.*;

/**
 * @author josh
 */

var nodes:Node[];

for(n in [0..2]) {
    var i = Image {
        backgroundLoading: true
        width: 800
        height: 618
        preserveRatio: true
        smooth: true
        url: ""
    };
}


var n = 0;
Stage {
    title: "Application title"
    width: 500
    height: 500
    scene: Scene {
        content: [
            Rectangle { fill: Color.RED width: 200 height: 200
            onMousePressed: function(e) {
                insert Rectangle { width: 50 height: 50 translateX: n * 20 translateY: n*20 fill: Color.GREEN } into nodes;
                insert ImageView {
                        translateX: n*20
                        translateY: n*20
                        image: Image {
                            backgroundLoading: true
                            width: 100
                            height: 100
                            url: "http://antwrp.gsfc.nasa.gov/image/0905/StarryNight-of-Brazil_LinesTafreshi.jpg"
                        };
                } into nodes;
                n++;
            }

            }
            Group {
                content: bind nodes
            }
        ]
    }
}